The Center model employed by the National Center for Rehabilitative Auditory Research (NCRAR) uses core funding to provide infrastructure that supports core investigators, who then leverage this support to garner external peer-reviewed funding, and to support education/outreach activities. Research is planned in the areas of Diagnosis and Assessment, Rehabilitation, and Prevention of auditory and balance dysfunction in Veterans. Education/outreach programs will include biennial conferences, a monthly seminar series, NIH-funded T-35 audiology student research training, and year-long externships for 4th year Audiology doctoral, Au.D., students in collaboration with the VA Portland Health Care System (VAPORHCS) Audiology Service. Technology-wise, further development in commercialization is planned for NCRAR's OtoID, a patented high-frequency portable audiometer, and for an upgrade to the patented Tinnitus Evaluation System (TES) to a tablet form factor, which would enable it to be used either in the clinic or in the Veteran's home. Some examples of studies planned in each of three key research areas are: Diagnosis and Assessment 1) characterize the impact of cochlear outer hair cell loss on physiological indicators of synaptopathy resulting in so-called “hidden hearing loss”, and clarify the perceptual consequences of this type of auditory damage; 2) study the pathophysiology and clinical phenotype of decreased sound tolerance (DST) and evaluate its auditory and psychological biomarkers; 3) evaluate the effects of blast exposure, TBI, and PTSD on hearing, tinnitus, and balance disorders over Veterans' lifetimes as part of the larger “Long-term Impact of Military-relevant Brain Injury Consortium (LIMBIC)” DoD/VA study; 4) use the computer-automated TES to expand normative data for the proper interpretation of tinnitus psychoacoustic testing; and 5) evaluate the ability of the brain to merge vestibular and visual streams of sensory information correctly in time to maintain balance and orientation. Rehabilitation 1) evaluate the long-term acclimatization effects obtained with hearing aids to improve hearing aid success among Veterans, and evaluate the effects of combining tests of speech understanding in noise, electrophysiology, behavioral tests of cognition, and tinnitus benefit to determine the changes in perception that occur after a hearing aid fitting; 2) evaluate the use of low-gain hearing aids for the management of tinnitus and their effect on communication in Veterans with normal or near-normal hearing; 3) adapt an interprofessional model for diagnosing and treating somatosensory tinnitus for a VA population; 4) participate in two collaborative multi-site randomized clinical trials of prescription medications for the treatment of tinnitus; 5) evaluate the ability of “stochastic resonance” supplied by a small amount of electrical current to increase the sensitivity of the damaged vestibular system and increase its effectiveness in older peop...